Tree Roots and Blocked Drains in Sydney: Cracking the Code of Your Gorgeous Fig Tree that is Ruining your Drainage System

One of Sydney’s great urban trees is that magnificent Moreton Bay fig tree on your nature strip. It’s also likely in your sewer pipe now; developing a root matrix which will likely clog your sewer in another year.

Tree root intrusion is the number one cause of sewer blockages in Sydney’s established suburbs. Not wet wipes. Not grease. Most of the blocked drain call-outs that we attend are due to roots in the terracottas, which are 50-100 years old in the older residential zones where mature trees have been around for decades to find them.

The mechanism is so simple and elegant. Warm, moist and nutritive water is found in sewer pipes. Those are the three things that tree roots are searching for. The Terracotta pipes, installed in one metre sections with joints cemented, crack or joint separate after decades of underfloor movement, temperature variations and in general deterioration. Each crack is an invitation. Each joint that is separated is an open door. The roots don’t lob in, they creep in where there are holes to get in in the first place.

Which Trees Cause the Most Damage in Sydney

Not all trees are created equal in terms of their offense. Some species are more prone to having root systems that are more aggressive in looking for water, and more aggressive in taking advantage of pipe defects.

Moreton Bay Fig (Ficus macrophylla): The worst of the various offenders in Sydney’s Eastern Suburbs. Roots systems may reach 20 to 30 metres out from the trunk and single trees along nature strip may extend to sewer pipes on both sides of the street, and to several houses in each direction. The roots are robust, tough and hard to destroy.

Port Jackson Fig (Ficus rubiginosa): native of Sydney and Sydney suburbs. Not as aggressive as the Moreton Bay; significant root intruder.

Jacaranda: It looks good in bloom, but bad below ground level. Common in inner west and eastern suburbs of Sydney with root systems that seek moisture in sewer lines.

Liquidambar: A popular street tree; has extensive lateral root system often getting into sewer & storm water pipes.

Eucalypts and paperbarks: Native species; their root systems vary according to species, but their roots can be a problem and cause a lot of intrusion especially in sandy or loamy soils, where they can spread with root riding leeway.

Sydney Water does not recommend planting of any tree nearer than 6 metres from a WW pipe. Learn the locations of your sewerage lines on your property by using Sydni Water Tap in®, a web portal that presents the sewerage service diagrams.

What Does Root Intrusion Look Like?

Usually while we do a camera inspection of a line that has roots, there will be 1 of 3 phases.

Early stage: Very thin strands of hair going into a joint or crack. There is a little restriction on the flow (there is movement but somewhat limited). Usually nothing is noticeable to the home owner at this point. It’s the most cost effective time period to intervene – clean the roots, re-line damaged areas in the joints and the issue is a thing of the past.

Mid stage: The roots have been growing inside the pipe, creating a netting effect which traps material as it flows. Clearly drains are slower. Gurgling of the toilet after flushing. An external grate can give a slight odour of sewage. This is when most individuals call in a plumber.

Advanced: Root mass very much clogs pipe bore. It does not allow much waste material to seep through. Sewage backup occurs via yard overflow relief gully and/or lowest indoor fixture. In this case the roots have displaced and/or fractured sections of pipe and clearing the root is not an adequate corrective measure, as the pipe is broken.

According to Sydney Water, the most frequent reason for sewer blockages happens to be from the tree roots that penetrate small cracks in the wastewater pipes. It advises consultation through Sydney Water Tap in® portal for a sewerage service diagram prior to planting any tree, and retention of at least 6 metres gap from trees and pipes. Consult local nurseries for species that do not have aggressive roots.

Jetting Vs. Relining: What Really Works!

During a root blockage clearance we employ a high powered water jetting machine, which is the best method of cutting through the root mass and opening up the free way. Jetting is a good system for a simple root removal process, eventually removing the roots and recreating a normal pipe flow.

But here comes the crucial question which distinguishes a quick solution from a forever solution: Is the entry still wide open?

After jetting, there could still be openings where the roots got into the pipe if the joints are broken or sections about the pipe have split apart. The roots will grow out again. When we have experienced re-blockage usually occurs within 6-18 months due to root regrowth. Thus, the homeowner spends $400 to $600 for a clearing once per year or so, and during that 5 years, the homeowner has spent $2000 to $3000 without ever addressing the core issue.

The entry points are permanently closed with Pipe relining. The resin impregnated liner is placed into the pipe, inflated on to the pipe wall and then located in place and cured. The end product is a completely continuous, smooth pipe within the existing pipe. Without any joints there will be no entry points. No entry points means no root regrowth! The relining products are warranted for 35 to 50 years life.

The price for re-lining the affected area is about 2-3 years of repeated jetting but the re-lining eliminates the problem forever. Reline is the maths always when there is a recurring problem with a root blockage.

What About This Council Tree?

If the roots which have caused the block have originated from a council owned tree (a street tree or tree in a public reserve) you may be able to get some help from your local council. Waverley Council has drain blockage guidelines which dictate when the Council will accept responsibility for damage to drains by Council trees.

It usually involves a sewer service diagram of your property, proving sewer pipe maintenance, and then evidence obtained from CCTV that proves a higher council tree has caused root intrusion issues in your sewer pipes. This documentation is included with all drain clearing services involving roots; we know that our customers may need it to go to council and supply it as part of all our drain clearing services.

Annual CCTV drain inspections are the one best investment you’ll be able to make if you live in an established Sydney suburb with mature trees and terracotta pipes. A survey costs $200 to $400 and a root problem is caught at an early stage where there is no need to dig up for clearing an area that is likely to become re-infected. When it gets to the point where the drain clogs up it is more expensive, it means your house stops functioning, and can lead to sewage backup causing a health hazard and insurance liability.